SS Montebello

Scientists diving off the California coastline to investigate the wreck of the SS Montebello, an oil tanker sunk in 1941 by a Japanese submarine, reported Thursday that the ship -- which was believed to hold up to 3 million gallons of oil -- had none of it remaining.

The news came as a relief to biologists, the Coast Guard and environmental groups, who were worried that the hull of the ship, sitting in 1,000 feet of water six miles west of Cambria, might one day rust open, potentially causing a huge oil spill across the California coast.

But after more than a week of high-tech imaging and drilling into the side of the aging hulk, scientists confirmed that the sunken ship's 32 oil tanks now hold only seawater. In other words, enough oil to fill the gas tanks of roughly 70,000 cars is gone, and nobody knows what happened to it.

"It could have been a slow gradual leak over many years since 1941. It could have all come up the day the ship was sunk in 1941. Basically, who knows? We'll probably never know," said Coast Guard spokesman Adam Eggers.

After Pearl Harbor

Environmental groups cheered the news.

"Stories featuring sunken boats and large volumes of oil don't usually have a happy ending. It's a welcome change," said Kaitilin Gaffney, Pacific program director for the Ocean Conservancy, an environmental group with offices in Santa Cruz.

The attack on the Montebello is not widely known today. But the ship's sinking made big headlines in 1941.

On Dec. 23, 1941, just 16 days after the bombing of Pearl Harbor, the tanker left Port San Luis in San Luis Obispo County shortly after 1 a.m., bound north for refineries in British Columbia.

Documents show the ship was carrying 75,346 barrels of crude oil -- about 3.1 million gallons. By comparison, the Exxon Valdez spilled 11 million gallons into Alaska's Prince William Sound.